Support tracking lifetime of component

ListKit.xcodeproj/ListKitTests_Info.plist

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>$(EXECUTABLE_NAME)</string>
+  <key>CFBundleIdentifier</key>
+  <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>$(PRODUCT_NAME)</string>
+  <key>CFBundlePackageType</key>
+  <string>BNDL</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>$(CURRENT_PROJECT_VERSION)</string>
+  <key>NSPrincipalClass</key>
+  <string></string>
+</dict>
+</plist>

ListKit.xcodeproj/ListKit_Info.plist

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>$(EXECUTABLE_NAME)</string>
+  <key>CFBundleIdentifier</key>
+  <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>$(PRODUCT_NAME)</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>$(CURRENT_PROJECT_VERSION)</string>
+  <key>NSPrincipalClass</key>
+  <string></string>
+</dict>
+</plist>

ListKit.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

ListKit.xcodeproj/project.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>IDEWorkspaceSharedSettings_AutocreateContextsIfNeeded</key>
+    <false/>
+</dict>
+</plist>

ListKit.xcodeproj/xcshareddata/xcschemes/ListKit-Package.xcscheme

@@ -0,0 +1,68 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "9999"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "ListKit::ListKit"
+               BuildableName = "ListKit.framework"
+               BlueprintName = "ListKit"
+               ReferencedContainer = "container:ListKit.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "ListKit::ListKitTests"
+               BuildableName = "ListKitTests.xctest"
+               BlueprintName = "ListKitTests"
+               ReferencedContainer = "container:ListKit.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

README.md

@@ -324,7 +324,7 @@ ListKit only support Swift Package Manager.
 
 ```swift
 dependencies: [
-    .package(url: "https://github.com/ReactComponentKit/ListKit.git", from: "1.0.0"),
+    .package(url: "https://github.com/ReactComponentKit/ListKit.git", from: "1.1.0"),
 ]
 ```
 
@@ -394,6 +394,10 @@ dependencies: [
   - The amount of space added around the content of the component to adjust its final size after its position is computed.
 - `func supplementComponents() -> [AnySupplementaryComponent]`
   - An array of the supplementary items attached to the component. 
+- `func willDisplay(content: Content)`
+  - Component's content is about to be displayed in the collection view.
+- `func didEndDisplay(content: Content)`
+  - Component's content was removed from the collection view.
 - `func render(in content: Content)`
   - Render data to component's content view 
 

Sources/ListKit/Common/ComponentQueryable.swift

@@ -0,0 +1,24 @@
+//
+//  ComponentQueryable.swift
+//  ListKit
+//
+//  Created by burt on 2021/09/19.
+//
+import UIKit
+
+public protocol ComponentQueryable: ComposeLayoutProvider {
+    /// Query AnyComponent at IndexPath
+    func anyComponent(at indexPath: IndexPath) -> AnyComponent?
+    /// Query AnyComponent at IndexPath and casting it to T type if exists
+    func component<T>(at indexPath: IndexPath, to: T.Type) -> T?
+}
+
+extension ComponentQueryable {
+    public func anyComponent(at indexPath: IndexPath) -> AnyComponent? {
+        return self.layout?.sections[indexPath.section].components[indexPath.item].component
+    }
+
+    public func component<T>(at indexPath: IndexPath, to type: T.Type) -> T? {
+        return self.layout?.sections[indexPath.section].components[indexPath.item].component.to(type)
+    }
+}

Sources/ListKit/Common/ComposeLayoutProvider.swift

@@ -0,0 +1,12 @@
+//
+//  ComposeLayoutProvider.swift
+//  ListKit
+//
+//  Created by burt on 2021/09/19.
+//
+import Foundation
+
+public protocol ComposeLayoutProvider {
+    /// UICollectionView's current compose layout
+    var layout: ComposeLayout? { get set }
+}

Sources/ListKit/DataSource/DiffableDataSource.swift

@@ -7,7 +7,7 @@
 
 import UIKit
 
-open class DiffableDataSource: DataSource {
+open class DiffableDataSource: ListKitDataSource {
     public var layout: ComposeLayout?
     public weak var collectionView: UICollectionView?
     private var dataSource: UICollectionViewDiffableDataSource<Section, AnyComponent>?
@@ -22,8 +22,8 @@ open class DiffableDataSource: DataSource {
                 let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ListKitCell.className, for: indexPath)
                 self?.configure(cell: cell)
                 if let wrapper = self?.layout?.sections[indexPath.section].components[indexPath.item], let contentView = wrapper.component.contentView() as? UIView {
-                    cell.contentView.viewWithTag(Int.max)?.removeFromSuperview()
-                    contentView.tag = Int.max
+                    cell.contentView.viewWithTag(ListKit.componentContentViewTag)?.removeFromSuperview()
+                    contentView.tag = ListKit.componentContentViewTag
                     cell.contentView.addSubview(contentView)
 
                     contentView.translatesAutoresizingMaskIntoConstraints = false
@@ -45,8 +45,8 @@ open class DiffableDataSource: DataSource {
                 let view = collectionView.dequeueReusableSupplementaryView(ofKind: ListKitReusableView.className, withReuseIdentifier: ListKitReusableView.className, for: indexPath)
                 if let anySupplementaryComponent = SupplementaryComponentManager.shared[kind], let contentView = anySupplementaryComponent.contentView() as? UIView {
 
-                    view.viewWithTag(Int.max)?.removeFromSuperview()
-                    contentView.tag = Int.max
+                    view.viewWithTag(ListKit.componentContentViewTag)?.removeFromSuperview()
+                    contentView.tag = ListKit.componentContentViewTag
                     view.addSubview(contentView)
 
                     contentView.translatesAutoresizingMaskIntoConstraints = false

Sources/ListKit/DataSource/ListKitDataSource.swift

@@ -0,0 +1,15 @@
+//
+//  DataSource.swift
+//  ListKit
+//
+//  Created by burt on 2021/09/11.
+//
+
+import UIKit
+
+public protocol ListKitDataSource: ComponentQueryable {
+    /// UICollectionView that uses this DataSource
+    var collectionView: UICollectionView? { get set }
+    /// Configure UICollectionViewCell if needed
+    func configure(cell: UICollectionViewCell)
+}

Sources/ListKit/DataSource/PlainDataSource.swift

@@ -7,7 +7,7 @@
 
 import UIKit
 
-open class PlainDataSource: NSObject, DataSource, UICollectionViewDataSource {
+open class PlainDataSource: NSObject, ListKitDataSource, UICollectionViewDataSource {
     public var layout: ComposeLayout?
     public weak var collectionView: UICollectionView?
 
@@ -25,8 +25,8 @@ open class PlainDataSource: NSObject, DataSource, UICollectionViewDataSource {
         let cell = collectionView.dequeueReusableCell(withReuseIdentifier: ListKitCell.className, for: indexPath)
         configure(cell: cell)
         if let wrapper = layout?.sections[indexPath.section].components[indexPath.item], let contentView = wrapper.component.contentView() as? UIView {
-            cell.contentView.viewWithTag(Int.max)?.removeFromSuperview()
-            contentView.tag = Int.max
+            cell.contentView.viewWithTag(ListKit.componentContentViewTag)?.removeFromSuperview()
+            contentView.tag = ListKit.componentContentViewTag
             cell.contentView.addSubview(contentView)
 
             contentView.translatesAutoresizingMaskIntoConstraints = false
@@ -48,8 +48,8 @@ open class PlainDataSource: NSObject, DataSource, UICollectionViewDataSource {
         let view = collectionView.dequeueReusableSupplementaryView(ofKind: ListKitReusableView.className, withReuseIdentifier: ListKitReusableView.className, for: indexPath)
         if let anySupplementaryComponent = SupplementaryComponentManager.shared[kind], let contentView = anySupplementaryComponent.contentView() as? UIView {
 
-            view.viewWithTag(Int.max)?.removeFromSuperview()
-            contentView.tag = Int.max
+            view.viewWithTag(ListKit.componentContentViewTag)?.removeFromSuperview()
+            contentView.tag = ListKit.componentContentViewTag
             view.addSubview(contentView)
 
             contentView.translatesAutoresizingMaskIntoConstraints = false

Sources/ListKit/Delegate/ComponentLifeTimeTrackingDelegate.swift

@@ -0,0 +1,24 @@
+//
+//  ComponentLifeTimeTrackingDelegate.swift
+//  ListKit
+//
+//  Created by burt on 2021/09/19.
+//
+
+import UIKit
+
+open class ComponentLifeTimeTrackingDelegate: NSObject, ListKitDelegate, UICollectionViewDelegate {
+    public var layout: ComposeLayout?
+
+    open func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
+        if let component = anyComponent(at: indexPath), let contentView = cell.contentView.viewWithTag(ListKit.componentContentViewTag) {
+            component.willDisplay(content: contentView)
+        }
+    }
+
+    open func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
+        if let component = anyComponent(at: indexPath), let contentView = cell.contentView.viewWithTag(ListKit.componentContentViewTag) {
+            component.didEndDisplay(content: contentView)
+        }
+    }
+}

Sources/ListKit/Delegate/ListKitDelegate.swift

@@ -0,0 +1,12 @@
+//
+//  ListKitDelegate.swift
+//  ListKit
+//
+//  Created by burt on 2021/09/19.
+//
+
+import Foundation
+
+public protocol ListKitDelegate: ComponentQueryable {
+
+}

Sources/ListKit/Layout/Component.swift

@@ -22,6 +22,10 @@ public protocol Component: NSCollectionLayoutItemsConvertible, Hashable {
     func contentInsets() -> NSDirectionalEdgeInsets
     /// An array of the supplementary items attached to the component.
     func supplementComponents() -> [AnySupplementaryComponent]
+    /// Component's content is about to be displayed in the collection view.
+    func willDisplay(content: Content)
+    /// Component's content was removed from the collection view.
+    func didEndDisplay(content: Content)
     /// Render data to component's content view
     func render(in content: Content)
 }
@@ -52,6 +56,12 @@ extension Component {
         return []
     }
 
+    public func willDisplay(content: Content) {
+    }
+
+    public func didEndDisplay(content: Content) {
+    }
+
     public func toNSCollectionLayoutItems() -> [NSCollectionLayoutItem] {
         let registerable = supplementComponents()
         registerable.forEach { SupplementaryComponentManager.shared.append($0) }

Sources/ListKit/ListKit.swift

@@ -3,4 +3,10 @@
 //  ListKit
 //
 //  Created by burt on 2021/09/16.
-//
+//
+
+import Foundation
+
+public enum ListKit {
+    public static let componentContentViewTag = Int.max
+}